The invention relates to a platen belt, and more particularly, to a platen belt for flattening documents contained thereon.
In order to increase the throughput and other reproducing capabilities it is common practice to use document handlers with automatic electrostatographic reproducing apparatus. The document handlers are used to separate individual documents from a stack of documents to be copied, move them on to the viewing platen where they are registered, held until the required number of copies have been made and then moved onto an output collection point to be followed by successive documents in the stack. Such an automatic document handler must not only move the document but must accurately register it in a predetermined copying position to assure production of a complete and visually acceptable copy. If, for example, the document is situated on the platen in a skewed or misaligned position, the copy will reflect the same skew or misalignment. Furthermore, it must also be capable of accepting a maximum range of paper weights or material weights efficiently as documents copied may have to vary from very heavy papers to very light papers such as those known as onion skin. Typically document handlers that have been used in the prior art include those employing a wide friction belt to transport the documents across the viewing platen.
A difficulty with the prior art belts is that the flexibility required of the belts to be driven around supporting rolls prevents the belts from holding documents flat that may be wrinkled, pleated, bent, or folded. If the document does not lay flat on the platen glass, portions of the document may be outside the depth of focus of the system optics. This will result in out of focus and blurred images.
It would be desirable to overcome the small tolerances for depth of focus in prior art systems. It is an object, therefore of the present invention to provide a platen belt that is able to compensate for wrinkled, pleated, bent, or folded documents. It is another object of the present invention to provide a platen belt that is flexible in the direction to rotate around supporting rolls and yet is rigid in the direction to press and flatten wrinkled, pleated, bent, or folded documents onto the platen glass. Other objects and advantages of the invention will become apparent as the following description proceeds and the features of the invention will be set forth with particularly in the claims annexed to and forming a part of this specification.